In the method for manufacturing a solid-state imaging device, there are two types of method: The method to form color filter directly on solid-state imaging sensor (on-chip method), and the method to form color filter on a transparent substrate such as glass substrate and to bond this with solid-state imaging sensor by adhesive agent (bonnding method).
In order to increase the sensitivity of solid-state imaging device, it has been attempted in recent years to mount lens on front surface of solid-state imaging sensor and to improve the efficiency by increasing the converging property to the light receiving unit. FIG. 9 shows a cross-sectional view of such solid-state imaging device. As shown in this figure, each of the pixels 53 of color filter 52 is arranged on the front surface of light receiving units 51 of CCD 50, and lenses 54 are provided in alignment with each pixel 53. As the material suitable for forming lenses on color filter 52, there are various types of photosetting or thermosetting resin. Because the difference of refractive indices between the air (refractive index.apprxeq.1) and resin layer (refractive index.apprxeq.1.5 to 1.6) is relatively big, it is possible to obtain high converging effect for incident light 55 coming directly to lens 55 through the air 56.
In contrast, the refractive index of the photosetting or thermosetting resin used as adhesive agent in the bonding method is 1.5 to 1.6, and the difference of refractive index from that of lens unit formed on solid-state imaging sensor is too small. Accordingly, if it is in the same arrangement as on-chip method, converging effect is not obtained almost at all.
The object of the present invention is to offer a light converging color filter or monochromatic filter to be used for the bonding method and a method for manufacturing converging filter to solve the above problems of the conventinal bonding method.